|
Authors: B. A. Senjobi1* and A. O. Ogunkunle2
Journal of Agricultural Biotechnology and Sustainable Development Vol. 3(1), pp. 7–18, January 2011 ©2011 Academic Journals Corresponding author. E-mail: bolasenjobi@yahoo.com, bolasenjobi@gmail.com.
|
|
Abstract |
|
|
|
This study was designed to assess the extent to which land use types influence soil nutrients and productivity in Ogun State. Soils under four land uses were sampled for physical, chemical and biological analyses. The land use types studied were arable cropping (land use 1); oil palm (land use 2), secondary forest (land use 3) and building sites (land use 4). The results showed that soil nutrients vary from one land use type to another with respect to morphological properties such as colour, texture, structure and consistency. This soils have very high sand content (>90%), this decreases with depth thereby enhancing porosity, uptill a point of high clay content where permeability is hampered. Exchangeable bases, and acidity and silt: Clay ratios were generally low. Ca and Mg dominate the exchange complex, organic matter content, total nitrogen and effective cation exchange capacity were high in the surface soils compared to sub-surface. The reverse is the trend for available P. Extractable Zn and Cu relative to the critical levels established down the profile were very high and erratic. Soil nutrients depletion followed this order: Secondary forest < Oil palm < Arable cropping < Building sites. Soil depletion and degradation were very prominent under building sites and arable cropping. It was observed that the land use types employed on the study sites were not very compatible with the characteristics of the soil. However, since soil nutrients depletion were very high in all land uses, therefore, there must be a careful choice of appropriate use of land in order to reduce soil nutrients depletion and enhances soil productivity. In addition to the above, plausible land use approach, multiple cropping, organic mulching, contour ridge and cultivation of cover crops are recommended in order to minimize soil nutrients depletion which mostly accounted for major degradation in these plots. |